Information storing medium, information recording/reproducing apparatus for recording/reproducing information with respect to the same and tracking method using the same

ABSTRACT

A magnetic tape has a guide track for optically obtaining a tracking signal and an independent information track for storing information. The magnetic tape is partitioned into different kinds of zones. The guide tracks are provided with grooves or pits serving as tracking marks, and the tracking marks are selectively located in the zones depending on the kind of zone. Thus, the track spacing of the guide tracks in each zone can be increased, so that a tracking control can be performed for a high density recording medium without reducing the spot size of the light.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to an information storing medium,such as a magnetic disk or a magnetic tape, an optical disk, an opticalcard, or an optomagnetic disk, having information tracks for recordingor reproducing information, and separate guide tracks for generating atracking signal for performing tracking control. The present inventionalso relates to an information recording/reproducing apparatus forrecording/reproducing information with respect to such an informationstoring medium, and to a tracking method using such an informationstoring medium.

[0003] 2. Description of the Prior Art

[0004]FIG. 14 shows an example of the structure of a conventionalmagnetic tape serving as an information storing medium. Several seriesof information (three in FIG. 14) are recorded on this magnetic tape601. These series of information are called information tracks 602. Thespacing between an information track and its neighboring informationtrack is called information track spacing, and is denoted as Tp. Guidetracks 603 for optical tracking control also are arranged on themagnetic tape 601. The spacing between a guide track 603 and itsneighboring guide track 603 is called guide track spacing, and isdenoted as Gp. On the guide tracks 603, grooves are arranged as trackingmarks, having a suitable depth and width for being read optically.

[0005] There is a one-to-one correspondence between the guide tracks 603and the information tracks 602, and the values for Tp and Gp areidentical. Three light beams, emitted from an optical head, form threespots 701, 702 and 703 on the magnetic tape 601. The three spots 701,702 and 703 are arranged obliquely with respect to the guide tracks 603on the magnetic tape 601, and are irradiated at different positions inthe Y-direction. The three light beams reflected from the magnetic tape601 return to the optical head and enter a photo-detector. FIG. 15 is acircuit diagram showing a conventional example of obtaining a trackingsignal. The photo-detectors 801, 802 and 803 receive the light beams704, 705 and 706, and output a signal corresponding to the irradiatedlight amount. Here, the light beam 704 corresponds to the spot 701 onthe magnetic tape 601, the light beam 705 corresponds to the spot 702,and the light beam 706 corresponds to the spot 703. The signals outputfrom the photo-detectors 801 to 803 are sent to I-V amps 804 to 806,which give out a voltage signal. The signal given out by the I-V amp 804is called S10, the signal given out by the I-V amp 805 is called SMO,and the signal given out by the I-V amp 806 is called S20. Thedifferential amplifier circuit 807 receives the signals S10 and S20 andgives out a differential signal. The signal given out by thedifferential amplifier circuit 807 is the tracking signal, which isgiven out from a terminal 808.

[0006] This method for obtaining a tracking signal from the three lightbeams, is known as the three-beam method, for example in optical diskdrives.

[0007] As shown in FIG. 3 of the present invention explained below, theoptical head 300 and the magnetic head 301 lie on the same base and canbe moved into the Y-direction of the magnetic tape with a transfersystem 302. Based on the tracking signal obtained from the terminal 808,the magnetic head 301 performs a tracking control so that the magnetichead 301 is positioned above the information track 602 of the magnetictape 601.

[0008] Recording/reproduction with other information tracks is performedby track jumping to different guide tracks.

[0009] A method for obtaining a tracking signal of high density with aconventional spot size is disclosed in Publication of UnexaminedJapanese Patent Application (Tokkai) No. Hei 6-096453 (U.S. Pat. Nos.5,406,545 and 5,650,987). In this method, the track spacing of the servopattern region is twice the track spacing of the pit rows of the dataregion, two tracking signals with different phase are generated from theservo pattern region, and the product of the two tracking signals iscalculated to obtain a tracking signal that is suitable for reproducingthe pit rows of the data region. Consequently, the structure and thedisclosed technological principle is different from the presentinvention. FIG. 5 of Tokkai Hei 6-096453 is structurally similar to thepresent invention, but the information tracks and guide tracks of thepresent invention are coplanar, so that its configuration is differentfrom the present invention.

[0010] Tokkai Hei 6-052551 contains similar disclosures as Tokkai Hei6-96453, but its configuration and principle are different from thepresent invention.

[0011] The track spacing of the guide tracks is determined by the spotsize of the beams irradiated from the optical head. If the spot size isnot made small, there is the problem that the track spacing of theinformation tracks cannot be made small, and it is not possible to raisethe recording density.

SUMMARY OF THE INVENTION

[0012] It is an object of the present invention to achieve higherdensity with a simple optical system in the optical tracking signaldetection of, for example, a magnetic tape, and in light of the problemsof conventional apparatuses, to provide an information storing mediumwith high recording density allowing reliable tracking control withconventional spot sizes, an information recording/reproducing apparatusfor recording/reproducing information on such an information storingmedium, and a tracking method for performing tracking control with suchan information storing medium.

[0013] To achieve these objects, a first information storing medium inaccordance with the present invention has a guide track and anindependent information track for storing information, the informationstoring medium being partitioned into different kinds of zones, theguide tracks being provided with tracking marks, and the tracking marksbeing selectively located in the zones depending on the kind of zone.

[0014] Furthermore, to achieve these objects, a second informationstoring medium in accordance with the present invention is partitionedin N kinds of zones, and tracking marks in a first kind of zone arelocated in a first guide track and then every N tracks starting with thefirst guide track, i.e. on the (n·N+1)-th guide tracks (wherein n is anatural number), tracking marks in a second kind of zone are located ina second guide track adjacent to the first guide track and then every Ntracks starting with the second guide track, i.e. on the (n·N+2)-thguide tracks, and in this order, tracking marks in an N-th kind of zoneare located in an N-th guide track and then every N tracks starting withthe N-th guide track, i.e. on the (n·N+2)-th guide tracks.

[0015] In the first and second information storing medium, it ispreferable that the tracking marks are either one of concave portionsand convex portions on the information storing medium.

[0016] It is also preferable that the tracking marks have a reflectivitythat is different from that of another portion of the informationstoring medium.

[0017] It is also preferable that the information storing medium furthercomprises an optomagnetic recording film, wherein the tracking marks areformed in the optomagnetic recording film.

[0018] To achieve the above-mentioned objects, an informationrecording/reproducing apparatus in accordance with the present inventioncomprises:

[0019] an optical head for irradiating light onto an information storingmedium having a guide track and an independent information track forstoring information, wherein the information storing medium ispartitioned into different kinds of zones, and tracking marks on theguide tracks are selectively located in the zones depending on the kindof zone;

[0020] a tracking signal generation means for outputting a trackingsignal based on a signal that is output from the optical head;

[0021] a control means for performing tracking control based on thetracking signal; and

[0022] a recording/reproducing means for performing at least one ofrecording and reproducing information with respect to the informationstoring medium.

[0023] In this information recording/reproducing apparatus, it ispreferable that the tracking signal generation means further comprises:

[0024] a selection control means for controlling the selection of acertain kind of zone on the information storing medium partitioned intoa plurality of zones; and

[0025] a signal holding means for holding a signal obtained from aselected kind of zones.

[0026] To achieve the above-mentioned objects, a tracking methodperforms tracking control based on a signal obtained from a certain kindof zone that is selectively derived from signals obtained by irradiatinglight onto an information storing medium having a guide track and anindependent information track for storing information, the informationstoring medium being partitioned into different kinds of zones, andtracking marks on the guide tracks being selectively located in thezones depending on the kind of zone.

[0027] With these configurations and this method, it is possible toprovide an information storing medium with high recording densityallowing reliable tracking control with conventional spot sizes, aninformation recording/reproducing apparatus for recording/reproducinginformation on such an information storing medium, and a tracking methodfor performing tracking control with such an information storing medium.

BRIEF DESCRIPTION OF THE DRAWINGS

[0028]FIG. 1 is a diagram partially showing the configuration of amagnetic tape as an information storing medium in accordance with thefirst embodiment of the present invention.

[0029]FIG. 2(a) and FIG. 2(b) are a block diagram of a circuit forobtaining the tracking signal from an information storing medium of thefirst embodiment of the present invention, and a diagram of the signalwaveforms at various components.

[0030]FIG. 3 is a perspective diagram showing the configuration of amagnetic tape drive as an information recording/reproducing device inaccordance with the first embodiment of the present invention.

[0031]FIG. 4 is a perspective view partially showing the structure andthe arrangement of the grooves in the guide tracks on a magnetic tapeaccording to the first embodiment of the present invention.

[0032]FIG. 5 is a block diagram of another circuit example for obtainingthe tracking signal from an information storing medium of the firstembodiment of the present invention.

[0033]FIG. 6 is a perspective view partially showing the structure andthe arrangement of the pits in the guide tracks on the magnetic tape inthe first embodiment of the present invention.

[0034]FIG. 7 is a perspective view partially showing the structure andanother arrangement of the pits in the guide tracks on the magnetic tapein the first embodiment of the present invention.

[0035]FIG. 8 is a block diagram of yet another circuit example forobtaining the tracking signal from an information storing medium of thefirst embodiment of the present invention.

[0036]FIG. 9(a) is a diagram illustrating the configuration of theinformation tracks formed on the upper surface of a magnetic tape inanother configuration of a magnetic tape as an information storingmedium in accordance with the first embodiment of the present invention.

[0037]FIG. 9(b) is a perspective view of a magnetic tape in this otherconfiguration of a magnetic tape as an information storing medium inaccordance with the first embodiment of the present invention.

[0038]FIG. 9(c) is a diagram illustrating the configuration of the guidetracks formed on the lower surface of a magnetic tape in the otherconfiguration of a magnetic tape as an information storing medium inaccordance with the first embodiment of the present invention.

[0039]FIG. 10 is a partially cross-sectional and transparent perspectivediagram showing the configuration of a magnetic disk drive as aninformation recording/reproducing apparatus in accordance with the firstembodiment of the present invention.

[0040]FIG. 11 is a diagram partially showing the configuration of amagnetic disk as an information storing medium in accordance with thefirst embodiment of the present invention.

[0041]FIG. 12 is a perspective diagram showing-the configuration of afixed magnetic disk drive as an information recording/reproducingapparatus in accordance with the first embodiment of the presentinvention.

[0042]FIG. 13 is a diagram partially showing a configuration of amagnetic tape as an information storing medium in accordance with asecond embodiment of the present invention.

[0043]FIG. 14 is a diagram showing a configuration of a magnetic tape asa conventional example of an information storing medium.

[0044]FIG. 15 is a block diagram of a circuit for obtaining a trackingsignal from a conventional information storing medium.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0045] The following is a description of the preferred embodiments ofthe present invention, with reference to FIGS. 1 to 13. In all thedrawings, elements with the same symbols have the same function.

[0046] First Embodiment

[0047]FIG. 1 is a diagram showing the configuration of a magnetic tapeserving as an information storing medium in accordance with the firstembodiment of the present invention. Several series of information(eight in FIG. 1) are recorded on this magnetic tape 101 serving as theinformation storing medium. These series of information are calledinformation tracks 102. The spacing between an information track and itsneighboring information track is called information track spacing, andis denoted as Tp. Guide tracks 103 for optical tracking control also arearranged on the magnetic tape 101. Grooves 104 are arranged in the guidetracks 103 as tracking marks. The grooves 104 are convex or concaveportions having a suitable depth and width. Generally, a favorabletracking signal is generated when their depth is about one eighth to onequarter of the wavelength λ of the irradiated light. The magnetic tape101 is partitioned into a number of different zones, due to thearrangement of the grooves 104 in the guide tracks 103. In the exampleshown in FIG. 1 there are three kinds of zones 1 to 3. In zone 1, guidegrooves 104 are arranged at the outermost guide track 1031, the guidetrack 1034 three tracks away from there and the guide track 1037 againthree tracks away. In zone 2, grooves 104 are arranged in the guidetracks 1032, 1035, and 1038. In zone 3, grooves 104 are arranged in theguide tracks 1033, 1036, and 1039. The distance from a guide track inwhich a groove 104 is arranged to the next guide track in which a groove104 is arranged in a certain zone is called Gp. In this example,Gp=3×Tp. With this arrangement, the actual track spacing Gp of the guidetracks for each zone can be increased.

[0048] The three light beams emitted from the optical head 300 (see FIG.3) form the three spots 201, 202 and 203 on the magnetic tape 101. Thethree spots 201, 202 and 203 are arranged obliquely with respect to theguide tracks 103 on the magnetic tape 101, and are irradiated atdifferent positions in the Y-direction. The three light beams reflectedfrom the magnetic tape 101 return to the optical head and enter aphoto-detector.

[0049]FIG. 2(a) is a circuit diagram of the circuit serving as atracking signal generation means in this embodiment. The photo-detectors501, 502 and 503 receive the light beams 204, 205 and 206, and output asignal corresponding to the irradiated light amount. Here, the lightbeam 204 corresponds to the spot 201 on the magnetic tape 101, the lightbeam 205 corresponds to the spot 202, and the light beam 206 correspondsto the spot 203. The signals output from the photo-detectors 501 to 503are sent to I-V amps 504 to 506, which give out a voltage signal. Thesignal given out by the I-V amp 504 is called S1, the signal given outby the I-V amp 505 is called SM, and the signal given out by the I-V amp506 is called S2. The differential amplifier circuit 507 receives thesignals S1 and S2 and gives out a differential signal. The signal givenout by the differential amplifier circuit 507 is entered into asample-and-hold circuit 510 serving as a signal holding means. Thesample-and-hold circuit 510 receives the signal from the control circuit512, and samples and holds the tracking signal. The signal output fromthe sample-and-hold circuit 510 is given out from the terminal 508 asthe tracking signal. A clock generation circuit 511 receives the signalSM given out from the I-V amp 505, and outputs a clock signal having arising flank or a falling flank synchronous with the switching of thezones in which the guide tracks and information tracks are recorded. Acontrol circuit 512 serving as a selection control means receives anoutput signal from the clock generation circuit 511, and outputs acontrol signal that controls the sample-and-hold circuit such that aspecific kind of zone is derived selectively, the output signal of thedifferential amplifier circuit 507 is sampled in that zone, and thesignal is held for the other zones. Based on the tracking signalobtained from the terminal 508, the control means performs trackingcontrol. After the tracking signal has passed a phase compensationcircuit (not shown in the drawings) in the tracking control means, it isamplified by a transfer system drive circuit, and transmitted to themotive force of the transfer system. Thus, a tracking control can berealized that follows the spots 201, 202, and 203 with respect tomovements in a direction perpendicular to the information tracks 102.

[0050]FIG. 2(b) shows the signal waveform for all parts in FIG. 2(a). Inthis example, the signals show an example for when the spot 202 movesfrom the left to the right along the guide track 1035. The signal S1 inFIG. 2 is denoted as 401, the signal SM is denoted as 402, and thesignal S2 is denoted as 403. The difference signal which is output bythe differential amplifier circuit 507 is denoted as 404. Thedifferential amplifier circuit 507 outputs a difference signal of signalS1 and signal S2. The control signal that the control circuit 512 givesinto the sample-and-hold circuit 510 is denoted as 405. Here, an exampleis shown where the tracking signal is, obtained based on the groove 104in the zone 2. There is no sampling of the signal in zone 2, and thesignal is held for all other zones. In the method for attaining trackingwith the three-beam method, signals that are output from thedifferential amplifier circuit 507 are disturbed before and after theswitching of the zones, because the spot position differs in theX-direction. The control circuit 512 lets the sample-and-hold circuit510 sample under avoidance of this disturbance period.

[0051]FIG. 3 illustrates the configuration of a magnetic tape driveserving as an information recording/reproducing device. The optical head300 and the magnetic head 301 serving as a recording/reproducing meansare carried on the same base and can be moved by a transfer system 302in the width direction of the magnetic tape 101. Based on the trackingsignal obtained from the terminal 508, a tracking control is performedthat positions the magnetic head 301 above the information track 102 ofthe magnetic tape 101. The magnetic tape 101 is wound from a reel 351 toa reel 352 or, conversely, from the reel 352 to the reel 351, so thatthe magnetic head 301 and the magnetic tape move relatively to eachother, while information is recorded and/or reproduced.

[0052]FIG. 4 shows the pattern of the grooves 104 on the magnetic tape101. The grooves 104 are made of convex portions or concave portions onthe guide track 103 (in FIG. 4, they are convex portions).

[0053] Information can be recorded on and/or reproduced from otherinformation tracks by switching the zones for obtaining the trackingsignal and performing a track jump to different guide tracks.

[0054] The density of the information tracks can be increased withoutchanging the spot size on the magnetic tape by partitioning the guidetracks into several zones and arranging the guide grooves 104 serving astracking marks in suitable spacings, as shown in this embodiment. Thismakes it easy to realize an information storing medium with high densitywhile maintaining compatibility with conventional low densityinformation media.

[0055] Moreover, since the density of the information tracks can beincreased with the same spot size, the reliability of the tracking servocan be kept high.

[0056] And, since the spot size can be big, the optical system can besimplified and the optical head can be of lower precision, which reducesthe costs.

[0057] Here, there are three kinds of zones for the partitioning, butthe present invention is not limited to three kinds of zones, and thesame effect can be attained in information storing media whose zones arepartitioned into two or more kinds of zones.

[0058] Also, this embodiment has been explained for the case that themethod known as the three-beam method of, for example, optical diskdrives is used to attain a tracking signal, but the same effect can beattained, if the tracking control is performed using the method known asthe push-pull method of optical disk drives, selectively sampling andthen holding tracking signals obtained for each zone.

[0059]FIG. 5 shows the configuration of a circuit for obtaining atracking signal with the push-pull method. Only one light beam isirradiated from the optical head 300 onto the magnetic tape 101. Thelight beam is reflected by the magnetic tape 101 and irradiated onto aphoto-detector. The optical beam 205 on the photo-detector is convertedinto an electric signal, in accordance with the light amount on thedouble-partitioned detection regions 521 and 522. The I-V amps 523 and524 convert the signals output by the detection regions 521 and 522 fromcurrent signals into voltage signals. The differential amplifier circuit526 receives the output signal from the I-V amps 523 and 524, andoutputs a difference signal. The signal obtained from thesample-and-hold circuit 510 is a tracking signal obtained with theregular push-pull method. The signal that is output by the differentialamplifier circuit 526 is sampled or held with the sample-and-holdcircuit 510. On the other hand, an adding circuit 525 receives theoutput signal from the I-V amps 523 and 524,-and outputs a sum signal.The signal that is output by the adding circuit 525 is proportional tothe total light amount of the light beam 205. A clock generator circuitreceives the output signal from the adding circuit 525 and generates aclock signal, and the control circuit 512 determines the timing for thesampling and holding of the sample-and-hold circuit 510.

[0060] Because in this case there is only one beam that is given out bythe optical head, the configuration of the optical head can be simple.Moreover, because the period in which the signal is disturbed whenswitching the zones becomes shorter, the period for sampling with thesample-and-hold circuit can be extended.

[0061] When a tracking signal is obtained with such a method, the effectcan be attained that the density of the information tracks can beincreased even with a larger spot, if a magnetic tape 101 that is aninformation storing medium in accordance with the present invention isused.

[0062] Moreover, rows of pits 105′ serving as tracking marks can bearranged on the guide tracks 103′, as shown in FIG. 6. Also in thiscase, the information storing medium is partitioned into several kindsof zones, and the pit rows are arranged only in certain zones. Also inthis case, the same effect can be attained as when providing grooves 104as shown in FIG. 4. When tracking is attained by the three-beam method,the signals obtained from the light beam can be modulated by providingpit rows. If the pit length and the relative speed between informationstoring medium and light beam are maintained at a certain value, acertain modulation frequency for the signal is attained. By extractingthis specified modulation frequency with a band-pass filter in a circuitsystem, the influence of stray light or irregularities in thereflectivity of the information storing medium can be suppressed, and areliable tracking signal can be obtained.

[0063] It is also possible to offset the pits 105″ serving as thetracking marks alternatingly with respect to the guide track 103″, asshown in FIG. 7. In this case, a tracking signal can be obtained withthe method known as the sample-servo method with, for example, anoptical disk drive.

[0064]FIG. 8 shows the configuration of a circuit for obtaining atracking signal with the sample-servo method. A photo-detector 531converts the light beam 205′, which has been reflected by the magnetictape 101, into an electric signal, corresponding to the light amount.The signal that is output from the photo-detector 531 is converted bythe I-V amp 532 from a current signal into a voltage signal. The clockgeneration circuit 511 receives the output signal from the I-V amp 532,and generates a clock signal. The control circuit 533 receives the clocksignal, and controls the timing for sampling and holding with the twosample-and-hold circuits 534 and 535. The two sample-and-hold circuits534 and 535 sample and hold the output signal from the I-V amp 532. Thesample-and-hold circuit 534 samples and holds the signal with a timingthat is set when the light beam passes positions where pits 105 arearranged to the right of the guide track 103, and the sample-and-holdcircuit 535 samples and holds the signal with a timing that is set whenthe light beam passes positions where pits 105 are arranged to the leftof the guide track 103. The differential amplifier circuit 507 receivesthe output signals of the two sample-and-hold circuits 534 and 535, andoutputs a difference signal. The signal that is output from thedifferential amplifier circuit 507 is the tracking signal obtained by aregular sample-servo method. The sample-and-hold circuit 510 samples theoutput of the differential amplifier circuit 507, and holds it. Thecontrol circuit 512 receives the clock signal, and determines the timingfor sampling and holding of the sample-and-hold circuit 510.

[0065] In this embodiment, there is only one beam output from theoptical head, and the configuration of the photo-detector can besimplified, so that the configuration of the optical head can besimplified. Obtaining a tracking signal with this technique brings aboutthe effect that the density of the information tracks can be increasedeven with a large spot, if a magnetic tape 101 that is an informationstoring medium in accordance with the present invention is used.

[0066] The convex portions or concave portions of the tracking marks canbe formed by several methods, for example, focussing a beam from a laser(for example, an argon ion laser) to form the tracking marks by thermaldeformation, or press-forming with a die.

[0067] As other examples for tracking marks, it is also possible to usemarks with different reflectivity, or marks with partially differentrefractive index, instead of the convex portions or concave portions. Toform marks with different reflectivity, any known technique, such asvapor deposition or printing, can be applied.

[0068] It is also possible to arrange magnetic marks similarly to thepits 105 in FIG. 7, and obtain a tracking signal by detecting thesemarks with an optomagnetic head.

[0069] Moreover, it is also possible to arrange the information tracksand the guide tracks on the front side and the rear side of a magnetictape 111 serving as the information storing medium, as shown in FIG. 9.In FIG. 9, information tracks 112 are lined up at a spacing Tp on thefront side of the magnetic tape 111, and guide tracks 113 are arrangedon the rear side. Like in the example of FIG. 1, the guide tracks 113are arranged in grooves 114. In this case, if the position of theinformation tracks on the front side matches that of the guide tracks,variations between different information recording/reproducingapparatuses can be suppressed, so that a reliable recording andreproducing of information becomes possible. Moreover, because guidetracks are not formed on the front side, information tracks can beformed in their place, and the information recording capacity can beincreased. If guide tracks and information tracks are formed ondifferent surfaces of the information storing medium, the surface wherethe information tracks are recorded can be a magnetic recording layer,and the surface where the guide tracks are recorded can be anoptomagnetic recording layer, that is, different recording layers can beused.

[0070] Moreover, when providing information tracks also on the rear sideof the magnetic tape shown in FIG. 1, it is also possible to provideinformation tracks on both sides, but guide tracks only on one side. Inthis case, the information recording density can be increased evenfurther. Also for this case, if the structure of the guide tracks asexplained for the present invention is used, a high recording densitycan be realized with a conventional spot size. When the numericalaperture NA of the focussing system of the optical head 300 is 0.04 andthe wavelength λ is 800 nm, the spot diameter on the magnetic tape 101is about 20 μm. In conventional examples, an information track spacingTp of about 20 μm was the limit. With the present embodiment, on theother hand, the information track spacing Tp can be as small as about 7μm by arranging grooves 104 in three kinds of zones of the magnetic tape101. And, if they are arranged in five kinds of zones, an informationtrack spacing of about 4 μm can be realized. Thus, a reliable trackingcontrol can be performed with a magnetic tape 101 with an informationrecording density that is three to five times higher, using aconventional optical head 300.

[0071] This embodiment has been explained by way of examples assuming amagnetic tape as the information storing medium and a magnetic tapedrive as the information recording/reproducing apparatus, but there isno limitation to this configuration. For example, it can also be appliedto disk-shaped media as shown in FIG. 10. In FIG. 10, the magnetic disk324 serving as the information storing medium is rotated by a motor 323.A transfer system 322 moves the optical head 320 and the magnetic head321 in the radial direction of the magnetic disk 324. A tracking signalis obtained by irradiating a light beam onto guide tracks 123 providedon the magnetic disk 324. Recording/reproducing information on themagnetic tracks 122 is performed with a magnetic head 321 serving as arecording/reproducing means.

[0072]FIG. 11 shows an example of how the magnetic tracks 122, the guidetracks 123, and the grooves 124 on the guide tracks are arranged. Thisconfiguration is substantially the same as the one shown in FIG. 1. InFIG. 1, the tracks and grooves are arranged in straight lines, whereasin the magnetic disk 324 in FIG. 11, they are arranged as concentricrings or as helical arcs. If such a magnetic disk 324 is used, theeffect of the present invention can be equally attained.

[0073] The above explanations related to magnetic disks, but the sameeffects of course also can be attained with optical disks oroptomagnetic disks, that record/reproduce information with light. Inthis case, instead of the magnetic head 321, an optical head isnecessary as a recording/reproducing means to record or reproduceinformation. Moreover, in combination with techniques forrecording/reproducing information in an optical head to obtain a largetracking signal (waveform equalization/crosstalk cancellation, PRML,Viterbi decoding, Irister, MAMMOS, magnetic domain magnificationreproduction, etc.), it is possible to perform the tracking and therecording/reproducing of information with a single head.

[0074] Here, PRML means partial response maximum likelihood compoundmethod, and Ailista is a method for improving the resolution of thereproduction signal by realizing a magnetic aperture using temperaturedifferences on the disk. MAMMOS is a method for improving resolutionwithout dropping the signal amplitude by magnetically enlarging therecorded marks.

[0075] Furthermore, the present embodiment also can be applied to fixedmagnetic disks (hard disks) as shown in FIG. 12. The optical head 330and the magnetic heads 331 are carried by arms 335, and moved insynchronization by a transfer system driving motor 336. On the bottomside of the magnetic disk 338, guide tracks 123 are arranged in circulararcs, and on the top side of the magnetic disk 338 as well as on bothsides of the magnetic disks 339, information tracks 122 are arranged inconcentric circles or in helical arcs. Grooves 124 are arranged in theguide tracks 123, like in FIG. 11. Tracking control is performed withthe tracking signal obtained with the guide tracks 123, and informationis recorded/reproduced on the information tracks 122. The effects of thepresent invention also can be attained with such a fixed magnetic disk.

[0076] Second Embodiment

[0077]FIG. 13 is another embodiment of the present invention. In FIG.13, the magnetic tape 131 serving as the information storing mediumshown in FIG. 1 of the first embodiment is provided with segment marks136, marking a series of zone segments. This allows the precisedetection of a targeted zone, and makes the tracking control even morereliable.

[0078] Moreover, if addresses are encoded and recorded in the segmentmarks 136, the retrieval of a position on the information storing mediumcan be made faster as well as more precise.

[0079] Like the first embodiment, this configuration can be applied notonly to the magnetic tape shown here, but also to magnetic disks,optical disks, and other information storing media.

What is claimed is:
 1. An information storing medium having guide tracksand independent information tracks for storing information, wherein theinformation storing medium is partitioned into different kinds of zones,the guide tracks are provided with tracking marks, and the trackingmarks are selectively located in the zones depending on the kind ofzone.
 2. The information storing medium of claim 1, wherein the trackingmarks are either one of concave portions and convex portions on theinformation storing medium.
 3. The information storing medium of claim1, wherein the tracking marks have a reflectivity that is different fromthat of another portion of the information storing medium.
 4. Theinformation storing medium of claim 1, further comprising anoptomagnetic recording film, wherein the tracking marks are formed inthe optomagnetic recording film.
 5. An information storing medium,partitioned in N kinds of zones, wherein tracking marks in a first kindof zone are located in a first guide track and in guide tracks providedevery N tracks starting with the first guide track, tracking marks in asecond kind of zone are located in a second guide track adjacent to thefirst guide track and in guide tracks provided every N tracks startingwith the second guide track, and in this order, tracking marks in anN-th kind of zone are located in an N-th guide track and in guide tracksprovided every N tracks starting with the N-th guide track.
 6. Theinformation storing medium of claim 5, wherein the tracking marks areeither one of concave portions and convex portions on the informationstoring medium.
 7. The information storing medium of claim 5, whereinthe tracking marks have a reflectivity that is different from that ofanother portion of the information storing medium.
 8. The informationstoring medium of claim 5, further comprising an optomagnetic recordingfilm, wherein the tracking marks are formed in the optomagneticrecording film.
 9. An information recording/reproducing apparatus,comprising: an optical head for irradiating light onto an informationstoring medium having guide tracks and independent information tracksfor storing information, wherein the information storing medium ispartitioned into different kinds of zones, and tracking marks on theguide tracks are selectively located in the zones depending on the kindof zone; a tracking signal generation means for outputting a trackingsignal based on a signal that is output from the optical head; a controlmeans for performing tracking control based on the tracking signal; anda recording/reproducing means for performing at least one of recordingand reproducing information with respect to the information storingmedium.
 10. The information recording/reproducing apparatus of claim 9,wherein the tracking signal generation means further comprises: aselection control means for controlling the selection of a certain kindof zones on the information storing medium partitioned into a pluralityof zones; and a signal holding means for holding a signal obtained froma selected kind of zones.
 11. A tracking method for performing trackingcontrol based on a signal obtained from a certain kind of zone that isselectively derived from signals obtained by irradiating light onto aninformation storing medium having a guide track and an independentinformation track for storing information, the information storingmedium being partitioned into different kinds of zones, and trackingmarks on the guide tracks being selectively located in the zonesdepending on the kind of zone.